Folia Morphologica

open access

Vol 79, No 1 (2020)
CASE REPORTS
Published online: 2019-06-04
Submitted: 2019-03-05
Accepted: 2019-05-29
Get Citation

Novel, bilateral, two-bellied muscles span the extensor forearm, thenar eminence to insert on the proximal phalanx of the thumb: clinical and embryological significance

P. L. Mishall, A. N. Marsh, D. Perez, X. H. Quezada, M. C. Stahl, R. E. Weinstock, S. A. Downie
DOI: 10.5603/FM.a2019.0067
·
Pubmed: 31169299
·
Folia Morphol 2020;79(1):182-187.

open access

Vol 79, No 1 (2020)
CASE REPORTS
Published online: 2019-06-04
Submitted: 2019-03-05
Accepted: 2019-05-29

Abstract

Muscle and tendon variations in the forearm, wrist and hand are commonly reported in the anatomical and surgical literature. They are frequently the source of inflammatory conditions such as de Quervain’s tenosynovitis or carpal tunnel syndrome. During academic dissection, a cadaver presented with bilateral, additional muscles running parallel to the abductor pollicis longus muscles (APL) in the extensor compartment of the forearm. Both additional muscles had two bellies, one proximal and one distal, with an intervening tendon. The proximal bellies were separate and distinct from the adjacent APLs. The tendons traversed the first dorsal compartments with the tendons of the APLs and the extensor pollicis brevis muscles (EPB). The distal bellies lay adjacent to the abductor pollicis brevis (APB) muscles in the thenar compartments, and inserted onto the volar base of the proximal phalanges of the thumbs. Following a thorough search of the literature, we determined that these additional muscles constitute a previously unreported variation. This report details the variation, compares it with other reported variations, presents the related embryology, and reviews the significance of this variation as it relates to inflammatory conditions and surgical procedures.

Abstract

Muscle and tendon variations in the forearm, wrist and hand are commonly reported in the anatomical and surgical literature. They are frequently the source of inflammatory conditions such as de Quervain’s tenosynovitis or carpal tunnel syndrome. During academic dissection, a cadaver presented with bilateral, additional muscles running parallel to the abductor pollicis longus muscles (APL) in the extensor compartment of the forearm. Both additional muscles had two bellies, one proximal and one distal, with an intervening tendon. The proximal bellies were separate and distinct from the adjacent APLs. The tendons traversed the first dorsal compartments with the tendons of the APLs and the extensor pollicis brevis muscles (EPB). The distal bellies lay adjacent to the abductor pollicis brevis (APB) muscles in the thenar compartments, and inserted onto the volar base of the proximal phalanges of the thumbs. Following a thorough search of the literature, we determined that these additional muscles constitute a previously unreported variation. This report details the variation, compares it with other reported variations, presents the related embryology, and reviews the significance of this variation as it relates to inflammatory conditions and surgical procedures.

Get Citation

Keywords

novel muscles, extensor compartment forearm, de Quervain’s syndrome

About this article
Title

Novel, bilateral, two-bellied muscles span the extensor forearm, thenar eminence to insert on the proximal phalanx of the thumb: clinical and embryological significance

Journal

Folia Morphologica

Issue

Vol 79, No 1 (2020)

Pages

182-187

Published online

2019-06-04

DOI

10.5603/FM.a2019.0067

Pubmed

31169299

Bibliographic record

Folia Morphol 2020;79(1):182-187.

Keywords

novel muscles
extensor compartment forearm
de Quervain’s syndrome

Authors

P. L. Mishall
A. N. Marsh
D. Perez
X. H. Quezada
M. C. Stahl
R. E. Weinstock
S. A. Downie

References (36)
  1. Akita K, Nimura A. Bergman's Comprehensive Encyclopedia of Human Anatomic Variation. In: Tubbs RS, Shoja MM, Loukas M (eds.). Forearm muscles. Wiley Blackwell, New Jersey 2016: 298–314.
  2. Baba MA. The accessory tendon of the abductor pollicis longus muscle. Anat Rec. 1954; 119(4): 541–547.
  3. Charles JP, Cappellari O, Spence AJ, et al. Musculoskeletal geometry, muscle architecture and functional specialisations of the mouse hindlimb. PLoS One. 2016; 11(4): e0147669.
  4. Chevallier A, Kieny M. On the role of the connective tissue in the patterning of the chick limb musculature. Wilehm Roux Arch Dev Biol. 1982; 191(4): 277–280.
  5. Chevallier A, Kieny M, Mauger A. Limb-somite relationship: origin of the limb musculature. J Embryol Exp Morphol. 1977; 41: 245–258.
  6. Dos Remédios C, Chapnikoff D, Wavreille G, et al. The abductor pollicis longus: relation between innervation, muscle bellies and number of tendinous slips. Surg Radiol Anat. 2005; 27(3): 243–248.
  7. Downie SA, Newman SA. Morphogenetic differences between fore and hind limb precartilage mesenchyme: relation to mechanisms of skeletal pattern formation. Dev Biol. 1994; 162(1): 195–208.
  8. El-Beshbishy RA, Abdel-Hamid GA. Variations of the abductor pollicis longus tendon: an anatomic study. Folia Morphol. 2013; 72(2): 161–166.
  9. Fabrizio P, Clemente F. A variation in the organization of abductor pollicis longus. Clinical Anatomy. 1996; 9(6): 371–375, doi: 10.1002/(sici)1098-2353(1996)9:6<371::aid-ca2>3.0.co;2-e.
  10. Franklin GM, Evanoff B. Treatment of Carpal Tunnel Syndrome: Surgery or More Conservative Management? Muscle Nerve. 2019; 60(1): 12–13.
  11. Georgiev GP, Tubbs RS, Iliev A, et al. Extensor indicis proprius muscle and its variants together with the extensor digitorum brevis manus muscle: a common classification. Clinical significance in hand and reconstructive surgery. Surg Radiol Anat. 2018; 40(3): 271–280.
  12. Giles KW. Anatomical variations affecting the surgery of de Quervain's disease. J Bone Joint Surg Br. 1960; 42-B: 352–355.
  13. Huisstede BMA, Coert JH, Fridén J, et al. European HANDGUIDE Group. Consensus on a multidisciplinary treatment guideline for de Quervain disease: results from the European HANDGUIDE study. Phys Ther. 2014; 94(8): 1095–1110.
  14. Kulthanan T, Chareonwat B. Variations in abductor pollicis longus and extensor pollicis brevis tendons in the Quervain syndrome: a surgical and anatomical study. Scand J Plast Reconstr Surg Hand Surg. 2007; 41(1): 36–38.
  15. Lacey T, Goldstein LA, Tobin CE. Anatomical and clinical study of the variations in the insertions of the abductor pollices longus tendon, associated with stenosing tendovaginitis. J Bone Joint Surg Am. 1951; 33-A(2): 347–350.
  16. Lee DH, Lee JH, Woo RS, et al. A rare bilateral variation on the dorsum of the hand: extensor digitorum brevis manus and extensor medii proprius. Anat Cell Biol. 2019; 52(1): 97–99.
  17. Li J, Ren ZF. Bilateral extensor medii proprius with split tendon of extensor indicis proprius, a rare anatomical variant. Romanian J Morphol Embryol. 2013; 54(3): 639–641.
  18. Mathew SJ, Hansen JM, Merrell AJ, et al. Connective tissue fibroblasts and Tcf4 regulate myogenesis. Development. 2011; 138(2): 371–384.
  19. McWhinnie DJ, Saunders J. Developmental patterns and specificities of alkaline phosphatase in the embryonic chick limb. Dev Biol. 1966; 14(2): 169–191.
  20. Mehta V, Arora J, Suri RK, et al. A rare quadruplicate arrangement of abductor pollicis longus tendons: anatomical and clinical relevance. Clinics (Sao Paulo). 2009; 64(2): 153–155.
  21. Moore JS. De Quervain's tenosynovitis. Stenosing tenosynovitis of the first dorsal compartment. J Occup Environ Med. 1997; 39(10): 990–1002.
  22. Moore KL, Dalley AF, Agur AMR. Essential Clinical Anatomy. Upper Limb. Wolters Kluwer, Philadelphia 2015: 398–482.
  23. Nayak SR, Krishnamurthy A, Pai MM, et al. Multiple variations of the extensor tendons of the forearm. Rom J Morphol Embryol. 2008; 49(1): 97–100.
  24. Nayak SR, Krishnamurthy A, Prabhu LV, et al. Anatomical variation of radial wrist extensor muscles: a study in cadavers. Clinics (Sao Paulo). 2008; 63(1): 85–90.
  25. Newman SA, Frisch HL. Dynamics of skeletal pattern formation in developing chick limb. Science. 1979; 205(4407): 662–668.
  26. Rai R, Ranade AV, Mamatha T, et al. A rare origin of abductor pollicis longus. Rom J Morphol Embryol. 2010; 51(2): 399–400.
  27. Ranade AV. Atypical insertion of the abductor pollicis longus muscle, an anatomical case report. Italian J Anat Embryol. 2017; 122(2): 147–150.
  28. Rogozinski B, Lourie GM. Dissatisfaction after first dorsal compartment release for de quervain tendinopathy. J Hand Surg Am. 2016; 41(1): 117–119.
  29. Saunders J, Gasseling M, Errick J. Inductive activity and enduring cellular constitution of a supernumerary apical ectodermal ridge grafted to the limb bud of the chick embryo. Dev Biol. 1976; 50(1): 16–25.
  30. Shipra P, Srijit D. Variant abductor pollicis longus muscle: a case report. Acta Medica (Hradec Kralove). 2007; 50(3): 213–215.
  31. Suwannakhan A, Tawonsawatruk T, Meemon K. Extensor tendons and variations of the medial four digits of hand: a cadaveric study. Surg Radiol Anat. 2016; 38(9): 1083–1093.
  32. Swinehart IT, Schlientz AJ, Quintanilla CA, et al. Hox11 genes are required for regional patterning and integration of muscle, tendon and bone. Development. 2013; 140(22): 4574–4582.
  33. Trivedi S, Siddiqui A, Sinha T, et al. Absence of extensor indicis: A rare anatomical variant. Int J Biom Res. 2014; 5(1): 61.
  34. van Oudenaarde E. Structure and function of the abductor pollicis longus muscle. J Anat. 1992; 174: 221–227.
  35. Yammine K. The prevalence of the extensor indicis tendon and its variants: a systematic review and meta-analysis. Surg Radiol Anat. 2015; 37(3): 247–254.
  36. Yuksel M, Onderoglu S, Arik Z. Case of an abductor pollicis longus muscle: variation or differentiation? Okajimas Folia Anat Jpn. 1992; 69(4): 169–171.

Important: This website uses cookies. More >>

The cookies allow us to identify your computer and find out details about your last visit. They remembering whether you've visited the site before, so that you remain logged in - or to help us work out how many new website visitors we get each month. Most internet browsers accept cookies automatically, but you can change the settings of your browser to erase cookies or prevent automatic acceptance if you prefer.

By  "Via Medica sp. z o.o." sp.k., Świętokrzyska 73, 80–180 Gdańsk, Poland

tel.:+48 58 320 94 94, faks:+48 58 320 94 60, e-mail:  viamedica@viamedica.pl